This invention relates to a process for the production of cell stimulating agents. More particularly, the invention relates to a process for obtaining a solution of cell respiration stimulating active agents from calves blood.
It is known from German Pat. No. 10 76 888 that one can obtain cell respiration stimulating active agents from bovine blood. In the process there described, one for example defibrinates fresh calve's blood, subjects the solution obtained to hemolyses, separates off the higher molecular weight components from the hemolysed solution obtained, such as in particular proteins, carries out a dialysis procedure and directly obtains a solution of active agent suitable for therapeutic uses by carrying out a subsequent mild concentration to a dry substance weight of 30 to 60 mg/ml. The dialysis required in this procedure can be carried out with any well known and conventional dialysis material to achieve the objects therein stated, whereby the use of cellophane tubes are indicated to be particularly suitable.
Although the above procedure does lead to a product with the desired therapeutic activity, it however possesses the disadvantage that the dialysis required is comparatively time-consuming and difficult to perform. Also, the product obtained is not the same uniform product since the upper molecular weight limit and accordingly its composition are subject to variations. Furthermore the yield of product obtained leaves much to be desired.
The process of the German Pat. No. 10 76 888 furthermore also leads to a product with a relatively high content of inorganic salts, in particular sodium chloride and potassium chloride. Such salts can not be separated off by the procedure therein described. The salt content of active agent solutions obtained can for example make up about 25 to 80% by weight of the solids content, so that corresponding injectable solutions or high concentration topical forms are several times hypertonic. As a result of this hypertonicity, intramuscular administration of such active agent solutions is on the one hand accompanied by pain and on the other hand by cell damage, which is disadvantageous to the desired cell regeneration effect.
The undesirable excessively high salt content of cell respiratory stimulating agents obtained by the procedure of the German Pat. No. 10 76 888 could in principle be lowered by several different methods, so that an isotonic or only slightly hypertonic solution of active agent is thereby obtained, namely for example by dialysis, ultrafiltration, ion-exchange or gel-filtration. All of these procedures are either not at all useable or are only useable with very unsatisfactory results. In accordance with German Pat. No. 25 12 936, the problem of desalting or partial desalting of the cell respiration stimulating active agent solution under discussion, should be solved by employing a very special gel-filtration procedure, namely by bringing the strongly salt-containing solution of the cell respiratory stimulating active agents into contact with a filtration layer situated on a perforated centrifuge drum and consisting of a gel with a high degree of cross-linking at a proportion of solution to gel volume of about 1:2.5 to 1.4.5. In this German Patent there are also at the same time described in detail the disadvantages of the other known procedures which are in principle possible for obtaining a partial desalting. All of these possible process procedures, including the process described in German Pat. No. 25 12 936, however, possess the disadvantage that their separation efficiency is very low and the apparatus required is very large, since as a rule these procedures have to be carried out at high dilutions. Furthermore, they are accompanied by higher or lower losses of active agent, since additional to the desired separation off of the inorganic salts, an adsorption of the cell respiration stimulating active agents on the separating medium also takes place. The essential regeneration of the gels and ion-exchange resin which is thereby necessary also requires a great amount of time and enables only a discontinuous working procedure with continuous change of the separating conditions.
The process for obtaining cell respiration stimulating active agents known from German Pat. No. 10 76 888, as a result of above, possesses the most differing disadvantages, and these could also not be solved by the additional considerations of the process described in German Pat. No. 25 12 936 for separating the excessively high content of disadvantageous inorganic salts.
It is therefore an object of the present invention to provide a new process for obtaining cell respiration stimulating active agents of the nature under discussion, which does not possess the disadvantages of the known working procedures and which can in particular be carried out simply and continuously, which is controllable in clean-cut fashion so that a product is obtained with a consistent upper--and to an extent also lower--molecular weight limit and further which leads directly to a solution of the cell respiration stimulating active agents by the provision of a controlled partial desalting procedure.